An elk knocked down a helicopter while its crew was capturing the animals in Utah's Wasatch County. The collision also killed the elk.
According to reports, the two-person crew was in the process of capturing the elk with a net when the animal "somehow jumped up and hit the tail rotor of the chopper".
Jared Rigby of the Wasatch County Sheriff's Office said that the helicopter was flying 10 feet (3 meters) above the ground in Currant Creek Reservoir.
After the crew failed to catch the animal by dropping a net, the pilot started slowing down so that one of the crew members could jump down and stop the elk by hobbling it. Mark Hadley with the state Division of Wildlife Resources said that as the helicopter slowed down, the elk collided with the rotor, thus bringing the aircraft down.
"The Australian flight crew was in the process of netting a cow elk, which jumped and hit the tail rotor of the helicopter," Wasatch County Search and Rescue said in a statement. "This almost severed the tail rotor and ended the flight of this chopper," it added.
Officials said that the crew sustained minor injuries. The elk, however, succumbed to its injuries.
"As for the chopper, not so good," the statement read. "Not something you see every day when an elk brings down a chopper."
The helicopter was contracted by the Utah Division of Wildlife Resources to help the Texas-based crew capture and sedate the elk and provide it with a tracking collar to analyse its movements.
According to Mark Hadley, helicopters are frequently used to monitor remote wildlife in Utah. The tracking collars help wildlife officials monitor elk migration paths and survival rates.
State officials said that they will be reviewing the incident to determine whether it was an accident or a fault on the crew's part.
A number of environmental protection groups have protested the use of helicopters to monitor wildlife. The group Wilderness Watch have objected to the Utah government's plan of studying mountain goats using choppers, calling the aircraft "unnecessary intrusion into some of our most treasured lands."